Like other natural phenomena, the Sun has been an object of veneration in many cultures throughout human history, and was the source of the word Sunday. Its formal name in the English language is, per the International Astronomical Union, the Sun (capitalized as a proper noun). The Latin name Sol , for the Sun god of the same name, is widely known but not common in general English language use; the adjectival form is the related word solar. "Sol" is, however, the modern word for "Sun" in many European languages.
The term sol is also used by planetary astronomers to refer to the duration of a solar day on another planet, such as Mars. A mean Earth solar day is approximately 24 hours, while a mean Martian 'sol' is 24 hours, 39 minutes, and 35.244 seconds. See also Timekeeping on Mars.